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The ebay injectors are worth buying in this case. The TB's are stripped bare, no sensors, good only for the servo motor.

I don't think injectors can be adjusted... they are what they are. They are either clean or dirty, which of course affects the flow..

raYzerman wrote: ↑Tue May 24, 2022 6:08 pm The ebay injectors are worth buying in this case. The TB's are stripped bare, no sensors, good only for the servo motor.

I don't think injectors can be adjusted... they are what they are. They are either clean or dirty, which of course affects the flow..

I was thinking about the mechanical stuff on the throttle bodies. Butterflies etc. I think he has already replaced the TPS - one of the early suspect parts. Vendor also has TPS for ~$50, I think, but that is one part I wouldn't buy used - especially from an early Gen III.

We did clean them in the ultrasonic with them being activated. I reverse flushed them as well, but that was rigged up, since there are no o-rings on the bottom of them and they have a long neck. I'm confident they are clean. They probably have been flushed and cleaned for several hours now.

I also don't have a reference point from Yamaha. What's acceptable from the factory? I'm positive they don't flow test them.

Ali-Express has them for $12 each. I think it's worth ordering 8 or so and flow testing them just for an experiment. Only issue is it takes 3-4 weeks to get them.

We aren't ignoring the advice of things to check, we're reading them and paying attention but we have limited time, so we're fiddling when we can, until we both get time to spend a whole day on it, swapping things and trying them all.

I'm simply just providing data back to you guys so you can see what we're trying and what's working or not working and maybe when this thread is over, we'll all have learned something. I know I will have.

I think I would choose used injectors that are OEM rather than new knockoffs. The Ali-Express stuff could be great or utter crap and a month from now, you could discover that they don't even fit.

I expect that the factory specifies flow and spray pattern under a specific feed pressure and it is up to the supplier to meet the specification. Pretty sure that Yamaha doesn't test...

I bought those eBay injectors with the fuel rail. We will see how they test.

Festus wrote: ↑Wed May 25, 2022 9:19 pm I bought those eBay injectors with the fuel rail. We will see how they test.

Good stuff! I'm betting they'll be good - at least you will be able to create a system with four matched injectors plus a couple of spares. Any idea what the device on the rail is between the first and second injector? (Or maybe between 3 and 4) Something that regulates pressure?

I don't know what that device is, other than a spring-loaded diaphram perhaps to buffer fuel rail pressure. The actual Fuel Pressure Regulator is part of the fuel pump assembly, excess pressure is just simply bled back into the tank. On Gen1, there was an FPR on the fuel rail with return hoses.

FJRoss wrote: ↑Wed May 25, 2022 9:30 pm

Festus wrote: ↑Wed May 25, 2022 9:19 pm I bought those eBay injectors with the fuel rail. We will see how they test.

Good stuff! I'm betting they'll be good - at least you will be able to create a system with four matched injectors plus a couple of spares. Any idea what the device on the rail is between the first and second injector? (Or maybe between 3 and 4) Something that regulates pressure?

I don’t know what that is. I’ll take a look once it arrives on Tuesday. I have grand visions of doing all sorts of vibration tests, measuring unbalanced and balanced injectors impact on vibration on the bars but I know me, and once they get here, I’ll test the flow and have them on the bike in no time with no measurements.

raYzerman wrote: ↑Wed May 25, 2022 9:47 pm I don't know what that device is, other than a spring-loaded diaphram perhaps to buffer fuel rail pressure. The actual Fuel Pressure Regulator is part of the fuel pump assembly, excess pressure is just simply bled back into the tank. On Gen1, there was an FPR on the fuel rail with return hoses.

I have not heard of it being mentioned before. Wonder if it could cause surging if not functioning properly...

Just for reference, the reason I focused on the injectors this time around was because my truck was surging and the issues looked exactly the same, one injector flowing more than the others, and when I got them in line, the surging stopped and the truck ran smooth. I was hoping that knowledge was going to transfer. The one injector that flows more, was leading me down that path, but on my truck, that bad injector was leaking as well, and the excess flow was due to it not closing all the way because of residue. With the FJR, the bad injector passes the leak test fine and it's clean, so I'm unable to stop the excess gas coming in.

Like mentioned earlier, this might have nothing to do with it at all, but that was my train of thought at the time.

FJRoss wrote: ↑Wed May 25, 2022 10:50 pm

raYzerman wrote: ↑Wed May 25, 2022 9:47 pm I don't know what that device is, other than a spring-loaded diaphram perhaps to buffer fuel rail pressure. The actual Fuel Pressure Regulator is part of the fuel pump assembly, excess pressure is just simply bled back into the tank. On Gen1, there was an FPR on the fuel rail with return hoses.

I have not heard of it being mentioned before. Wonder if it could cause surging if not functioning properly...

I would have doubts it would cause surging. The fuel pressure behind the injectors would be behind all of them equally, and the pore size and duration of injector opening would determine the amount of fuel sprayed into the intakes.

A new fuel pump was installed, but what hasn't changed is the FPR in the housing...... which may be OK. A fuel pressure test would confirm, which would be indicated if the surging followed the tank (swap). It will be interesting if matched injectors cure it.

raYzerman wrote: ↑Thu May 26, 2022 8:17 am It will be interesting if matched injectors cure it.

Very much so. I struggled for some time with a very uneven idle on my 2011 but no issues with surging while underway. It eventually went away by itself (after I bought a spare fuel rail/injectors on ebay but never installed). The previous owner had a "bad gas" event and had the injectors cleaned but there might have been some residual goo that took some time to clear out. I don't know but it has been flawless for the last 80,000 km.

I have spare refurbished Gen 2 injectors.. .sigh. Not much help here...

dcarver wrote: ↑Fri May 27, 2022 1:32 pm I have spare refurbished Gen 2 injectors.. .sigh. Not much help here...

Yeah, I think Gen I and II are the same but changed for Gen III. I remember your kind offer of the loan of an injector set when I was having issues. I got the fuel rail and four injectors for a little more than the cost of round- trip cross border shipping (and then never used them).

Hope this solves the problem!

The used injectors came today. Hooked all 4 up, only 1 sprayed anything. Wasn't thrilled, but they had a video of the bike running on the ebay ad, so I just thought about it a little, pumped up the test to higher volume and they all came on. Ran it 4-5 times and this is what it looked like.



This is where it ended up before I started messing with it...



I cleaned it a couple times in the ultrasonic. This is where I'm at with the original filters still installed. I'll pull them and clean them without the filters and put new filters in and see if that gets us across the finish line, but as you can see, it ended up not too bad. 3 really close and 1 with a higher flow. Same issue with had with Viper Dad's, but this set seems much more consistent than his.



There are various test conditions, idle speed, medium speed, and high speed testing. The idle and medium look really close. It's the high speed that isn't great.

They are looking pretty good. If you want to be fussy, use 2, 3 and 4 and the closest match from the original set. If these have been sitting, they may need a bunch of fuel and injector cleaner through them to settle. Are you going to use the "new" or the original fuel rail?

How does the spray pattern look and do any of them drip? The photo strobe test for spray pattern done by the injector cleaning companies could be very useful in identifying a bad or dirty injector!

What is the fuel volume (ml/min) for the high speed test? Does it represent a reasonable fuel consumption rate for an FJR at a fast cruise?

i.e. Reality check calculation...

120 km/hr / 18 km/L / 4 injectors / 60 min/hr x 1000 ml/L = 27.8 mL/minute for each injector at 120 km/hr or 75 mph.
No point in a test that runs 100 ml/minute.

What pressure does your device run at (close to FJR)? Any idea if the FJR increases pulse frequency or duration with application of throttle?

Interesting stuff!

Not sure on the rail yet, Ross. Haven’t thought that far ahead.

The spray patterns look good. I only had 30 minutes with them, so hopefully I can get then really close.

Great point about the fuel flow rate. It’s doing 100ml in about 35-40 seconds on high speed. Close to 100 ml in 60 seconds on medium.

I did do a leak test, no leaks. The pressure can be adjusted, but each cycle has its preset pressure and pulse rate. You can adjust both.

There are also acceleration tests that change as if you are on the throttle. I’ll have to see if the pulse rate changes during that.

100 mL in 60 seconds is almost four times the rate you would expect to see cruising at 75 mph. Rapid acceleration with a load is a much higher fuel consumption than cruise but I wouldn't expect a surge to be as noticeable under those conditions. Are you testing at close to the FJR's 50-ish psi?

By the time this is worked out, we will all have learned a few things!

Yes, I’m testing in that psi range.

I am a bit late to the game here but this sure seems like an in range sensor failure.

Ford had lots of issues with their early MAP sensors doing stuff like this. They ran on a duty cycle output and would end up reading 20% when they should read 60%. Since 20% was within the allowed range during engine operation, it never flagged a code.

The answer was to hook up the scan tool and drive it around the block and see what the manifold pressure was, and thank your lucky stars it wasn't a really old one that didn't output live data.

Older O2 sensors would do it too and they'd just be lazy and read rich, causing the fuel trims to lean out over time.

I am not sure if a '13 outputs data over the OBD port. If it does, it might be worth it to get a cheap logger and ride it for a while, then look at all the parameters. I am guessing you'll see one that looks "kind right but not really".

My other gut instinct is secondary ignition. I don't recall how the Gen III ignition looks, but on a car, I would start looking at the boots and wires. If possible, a nice misting of water from a spray bottle will show that issue in short order.

One thing is for sure, the last thing you check will be what fixes it.